Code Quick Cards

Grounding connects the system or equipment to earth; bonding establishes electrical continuity and an effective ground-fault current path. Exception/watch: Services, separately derived systems, and special occupancies each have...

Other metal piping systems likely to become energized shall be bonded as required by 250.104(B). Exception/watch: CSST systems can have manufacturer instructions and fuel-gas-code bonding requirements beyond the electrical rule.

If a metal underground water pipe qualifies as a grounding electrode, it shall be included in the grounding electrode system. Exception/watch: Electrode qualification depends on direct contact with earth for the required length and...

All grounding electrodes described in 250.52(A)(1) through (A)(7) that are present at a building or structure shall be bonded together to form the grounding electrode system. Exception/watch: Rod, pipe, plate, concrete-encased,...

The grounded service conductor shall be connected to the grounding electrode system as required by 250.24. Exception/watch: Existing installations and separately derived systems have separate provisions.

Separately derived alternating-current systems shall be grounded and bonded in accordance with 250.30 where required. Exception/watch: Some systems are not separately derived because of a direct electrical connection to another source...

Conductors shall have ampacity sufficient for the load after required adjustment and correction factors are applied. Exception/watch: Specific equipment articles, small-conductor rules, dwelling service/feeders, motors, HVAC, and...

A continuous load is a load where the maximum current is expected to continue for 3 hours or more. Exception/watch: Listed assemblies rated for 100% operation can have specific provisions.

AFCI protection shall be provided for the branch circuits and locations identified by the adopted edition of 210.12. Exception/watch: Check the adopted edition and local amendments for exceptions and extension rules.

Equipment grounding conductors shall be sized in accordance with 250.122 and the rating or setting of the circuit overcurrent device, subject to the article rules. Exception/watch: Specific equipment articles can require different or...

Motor full-load current used for conductor and branch-circuit short-circuit/ground-fault protection calculations is generally determined from the Article 430 tables as directed by 430.6. Exception/watch: Nameplate current is used...

Transformer secondary conductors shall be protected in accordance with one of the permitted 240.21(C) rule paths. Exception/watch: Outdoor secondary conductors and supervised industrial installations have separate provisions.

Every circuit and circuit modification shall be legibly identified as to its clear, evident, and specific purpose or use. Exception/watch: Existing directories should be corrected when circuit modifications make them inaccurate.

Indoor switchboards, switchgear, panelboards, and motor control centers shall have dedicated equipment space as required by 110.26(E). Exception/watch: Suspended ceilings with removable panels are not considered structural ceilings...

Voltage drop recommendations appear in informational notes and are design considerations rather than blanket mandatory ampacity requirements. Exception/watch: Sensitive loads and long runs can justify larger conductors even when...

A grounding electrode conductor shall be installed in one continuous length without a splice or joint except as permitted by 250.64(C). Exception/watch: The rule contains specific allowances for taps and busbar arrangements.

Boxes shall be of sufficient size to provide free space for all enclosed conductors. Exception/watch: Check listed box volume markings and applicable raceway-body rules.

Raceway fill is determined from the actual conductor areas and the permitted percentage of the raceway internal area. Exception/watch: Nipples not over 24 in. have a 60% fill allowance under the applicable Chapter 9 note.

GFCI protection shall be provided in the locations and for the outlets/equipment covered by the adopted edition of 210.8. Exception/watch: Specific listed exceptions and accessibility provisions must be checked in the adopted edition.

Disconnecting means shall be provided for the controller and motor as required by 430.102. Exception/watch: Lockable disconnect provisions can affect the within-sight requirement under applicable exceptions.

Transformer overcurrent protection shall be provided in accordance with 450.3 and the applicable table. Exception/watch: Supervised locations and transformers over or under specific impedance/voltage conditions can use different table...

Conductor ampacity shall be based on the temperature rating of the termination as required by 110.14(C). Exception/watch: Listed equipment identified for other conductor temperature ratings is used in accordance with its listing.

Working space about electrical equipment shall be provided and maintained to permit ready and safe operation and maintenance. Exception/watch: Special installations and existing conditions can involve other rules, but field...

Electrical equipment identified by 110.16 shall be field or factory marked to warn qualified persons of potential electric arc-flash hazards. Exception/watch: The NEC warning-marking rule is not a substitute for an NFPA 70E arc-flash...